🏷️ Basic Information Identification Make: Yamaha Model: YJ125S Year: 2003 Vehicle Type: Scooter 👋 Introduction Market Position Segment: Lightweight Scooter / Commuter Scooter Target Market: Urban commuters, riders seeking economical and maneuverable transportation. Competitive Analysis Competitors: Honda Dio, Suzuki Address, Kymco Agility, various other 125cc scooters from Japanese and Asian manufacturers. Key Features Features: Reliable air-cooled engine, automatic transmission, comfortable riding posture, lightweight and agile handling for city riding. 📋 Manual Details Coverage Areas Manual Type: Workshop Service Manual / Repair Manual Language: English Format: PDF Download Target Audience: Professional Technicians, Advanced DIY Mechanics 📖 Manual Coverage Systems Covered Engine: Complete disassembly, inspection, assembly, tuning, troubleshooting, and repair of the 125cc engine. Fuel System: Carburetor overhaul, fuel pump, fuel lines, and related components. Ignition System: CDI unit, spark plug, ignition coil testing and replacement. Cooling System: Air cooling system components and maintenance. Transmission: Automatic CVT (Continuously Variable Transmission) system maintenance, belt inspection, roller weights, and clutch assembly. Chassis Frame: Frame inspection, straightening procedures, and component mounting. Suspension: Front fork overhaul, rear shock absorber inspection and replacement. Brakes: Front and rear brake system maintenance, hydraulic lines, caliper overhaul, brake pad replacement, drum brake adjustment. Electrical System: Wiring diagrams, battery, starter motor, lighting system (headlight, taillight, turn signals), horn, instrumentation. Wheels Tires: Wheel bearing replacement, tire inspection, and inflation specifications. Bodywork Trim: Fairing removal and installation, seat, handlebars, and other cosmetic components. Procedures Included Maintenance: Routine service checks, oil changes, filter replacements, spark plug service, chain/belt adjustments, brake bleeding. Troubleshooting: Diagnostic charts for common problems, symptom-based solutions for engine, electrical, and mechanical issues. Repair: Detailed step-by-step instructions for component removal, overhaul, repair, and reinstallation. Disassembly Assembly: Comprehensive guides for full vehicle teardown and reconstruction. Torque Specifications: Critical torque values for all fasteners to ensure proper assembly and prevent damage. Electrical Diagnostics: Testing procedures for electrical components, continuity checks, and fault finding. Technical Depth Depth Level: Comprehensive, covering all aspects from basic maintenance to advanced engine and electrical system repairs. 📊 Manual Specifications File Format File Type: PDF Searchability: Likely text-searchable (dependent on original scan quality) Print Quality: Digital PDF, print quality depends on user's printer. Binding Type: N/A (Digital Download) Paper Type: N/A (Digital Download) Page Count: Estimated 200-300 pages (typical for a 125cc scooter workshop manual) ⚙️ Engine Specifications Primary Engine Engine Type: 4-stroke, OHC, forced air-cooled Displacement: 125cc (approximate, exact may vary slightly) Bore X Stroke: Refer to manual for precise specifications Compression Ratio: Refer to manual for precise specifications Performance Horsepower: Approximately 7-9 HP (typical for this class) Torque: Approximately 7-8 Nm (typical for this class) Fuel System Fuel Delivery: Carburetor (likely Mikuni or Keihin, specific model in manual) Fuel Type: Unleaded Gasoline Ignition Ignition Type: CDI (Capacitor Discharge Ignition) Lubrication Oil Type: Refer to manual for specific API/JASO specification (e.g., SAE 10W-40 API SG or higher, JASO MA) Oil Capacity: Refer to manual for precise capacity (typically around 0.8-1.0 liters) 🔧 Transmission Standard Transmission Type: Automatic, V-belt type Continuously Variable Transmission (CVT) Final Drive: Gear reduction, enclosed Features Clutch Type: Automatic centrifugal clutch 📐 Dimensions Exterior Length: Refer to manual for exact dimensions Width: Refer to manual for exact dimensions Height: Refer to manual for exact dimensions Weights Dry Weight: Approximately 100-110 kg (typical for this class) Wet Weight: Refer to manual for exact specification Payload Capacity: Refer to manual for specification (typically rider + small load) 🛡️ Safety Features Ratings Safety Certifications: Refer to local regulations and certifications for 2003 models. Active Features Brakes: Front disc brake, Rear drum brake (common configuration for this model year). Lighting: Headlight, taillight, brake light, turn signals for visibility. Passive Features Frame Construction: Underbone steel frame for structural integrity. Foot Peg Placement: Designed for rider stability. 💡 Technology Features Infotainment Instrument Cluster: Analog speedometer, fuel gauge, indicator lights (turn signals, high beam, oil pressure). Driver Assistance ABS: Not equipped as standard on this model year. Connectivity Connectivity Features: None (typical for scooters of this era). 🔧 Maintenance Service Intervals Oil Change Interval: Typically every 2,000-4,000 km or 6-12 months, refer to manual for exact mileage/time. Air Filter Service: Inspection every 2,000 km, cleaning/replacement as needed based on conditions. Spark Plug Replacement: Typically every 4,000-6,000 km, check manual for specific plug type and gap. Cvt Belt Inspection: Inspection recommended at 6,000-10,000 km for wear and damage. Valve Clearance Adjustment: Recommended interval varies, often between 6,000-12,000 km, critical for engine performance. Fluid Specifications Engine Oil Grade: SAE 10W-40 API SG or higher, JASO MA compliant (verify in manual). Brake Fluid Type: DOT 3 or DOT 4 brake fluid (verify in manual for front disc brake). Known Issues Common Wear Items: CVT belt, brake pads/shoes, tires, suspension bushings, battery. Potential Performance Degradation: Loss of power due to worn CVT components (rollers, belt), clogged carburetor jets, carbon buildup. Electrical Issues: Corrosion on connectors, faulty regulator/rectifier,...